Turret type belt grinding machine



Oct. 14, 1969 w, KQRTH EI'AL I 3,471,974'

TURRET TYPE BELT GRINDI NG MACHINE Filed March 29, 1966 2 Sheets-Sheet 1 [/VVE/VTORSI W/LL/ KORTH HERBERT Z/N/YZRMA/V/V y g' fil- Oct. 14, 1969 w. KORTH ETAL 3,471,974

TURRET TYPE BELT GRINDING MACHINE Filed March 29. 1966 2 Sheets-Sheet 2 [/VVE/VTORS:

BY wa ATT'Y United States Patent 3,471,974 TURRET TYPE BELT GRINDING MACHINE Willi Korth, 29 Bergstrasse, Ratzeburg, Germany, and Herbert Zimmermann, 43 Vierbergen, Ahrensburg, Germany Filed Mar. 29, 1966, Ser. No. 538,354 Int. Cl. B24b 21/18 US. Cl. 51-148 6 Claims ABSTRACT OF THE DISCLOSURE A belt grinding machine having four abrasive belts which are arranged in turret fashion and are laterally adjustable. The driving shaft which is normally braked is released by a brake coupling to change the working positions of the belts. Tension rollers accommodate grinding mandrels for carrying out fine grinding works. The abrasive belts and the grinding mandrels can be used simultaneously.

BACKGROUND OF THE INVENTION This invention relates to belt grinding machines, and more specifically to a turret type belt grinding machine.

Belt grinding machines are known in which on both sides of a stationary shaft so-called contact wheels are fixed around each of which an abrasive belt is led which, because of its great length, is held at a certain distance by a tension roller.

The disadvantage of such belt grinding machines consists in that frequently a workpiece cannot be completely finish ground on such a machine having, as a rule, no more than two abrasive belts, since e.g. the finish grinding of instruments, turbine blades or the like requires rough grinding, medium grinding, fine grinding and polish grinding with wheels of correspondingly different sizes due to the different radii of the workpiece. This fact means frequent and time-consuming rechucking of contact wheels and abrasive belts. In so doing, the machine elements running at a high speed must be braked until they come to a standstill and later be restarted. These difiiculties may be evaded by using several special grinding machines the installation and maintenance costs of which are, however, very high. Another disadvantage of these conventional belt grinding machines consists in that the parallelism of the axes of the resiliently mounted tension rollers in relation to the axes of the contact wheels can, indeed, be precisely adjusted but shifting of the tension roller in its axial direction, e.g. when using belts of difi'erent widths, for adjusting an edge-true travel of the belt in relation to the contact Wheel is not possible during the running of the machine.

SUMMARY OF THE INVENTION It is the object of the present invention to eliminate the above-mentioned disadvantages.

This object is achieved according to the present invention by providing a device having a plurality of abrasive belts, which comprises a rotatable carrier means mounting the abrasive belts in turret fashion, and contact wheels and tension rollers around which the abrasive belts are led as endless bands, the abrasive belts both with their contact wheels and their tension rollers being capable of being optionally brought, during the rotation of the carrier means, into any desired working position.

In this manner a plurality of abrasive belts with contact wheels and tension rollers are available on the machine and arranged so as to be rotatable about an axis in turret fashion. This permits not only to bring a greater number of abrasive belts into working position but also, by means of a locking facility, to adjust infinitely variably any desired working height in accordance with the size of the workpiece, a sedentary or standing practice of grinding and the operators height.

Another essential advantage of the invention consists in that the relatively small tension roller which may be constructed as a contact wheel and which in turn may be additionally equipped with means for the reception of grinding mandrels or the like, is now also available in appropriate working position for the grinding of workpieces of smaller radii at optimum grinding speed of the belt.

A further advantage resides in the particular construction of the tension roller which, as compared with the usual constructions of the tension roller, not only resiliently moves away from the contact wheel for the purpose of tensioning the abrasive belt and not only permits its axis to be adjusted parallel in relation to the axis of the contact wheel but which, as proposed by the present invention, is also capable of being laterally shifted in its axial direction.

This aifords the great advantage of an accurate adjustability of the abrasive belt with respect to its edgetrue travel both in relation to the edge of the contact wheel and in relation to a grinding table. It is often of great importance to be able to accurately grind with the edge of the abrasive belt into corners of the workpiece. Moreover, it is now also possible to have narrower abrasive belts run on wider contact wheels in a predetermined place on the contact wheel. Thus, for adjusting the accurate travel of the belt in relation to the edge of the contact wheel, it is no longer necessary, as was hitherto the case, to remove the contact wheel and to adapt it by pushing shims thereon.

As a further advantage the machine as proposed by the invention olfers the possibility of carrying out, in conjunction with the plurality of available abrasive belts, at the same time surface grinding and right-angle grinding operations on a workpiece by positioning an angularly adjustable worktable in any desired place at the actually desired grinding belt. In view of the advantageous possibility of placing the workpiece on the horizontal table, the adjustability of the abrasive belt in vertical direction to meet the respective working conditions offers the advantage of a very well controllable sequence of operations over a conventional horizontally running abrasive belt.

As it is often desired to have spindles of different lengths and diiferent diameters available for driving the contact wheels, the invention proposes to construct the driven spindles as hollow shafts in which then different spindles can be inserted.

BRIEF DESCRIPTION OF DRAWINGS One embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which:

FIG. 1 is a side elevational view, partly in section, of a turret type belt grinding machine according to the invention;

FIG. 2 is a front elevational view of the machine of FIG. 1;

FIG. 3 is a view of the bell-shaped coupling member and the associated switch adjusting device as seen in the direction of arrow A of FIG. 1;

FIG. 4 is a fragmentary front elevational view of the machine, showing a grinding table positioned at one of the abrasive belts;

FIG. 5 is a view of a tension roller as seen from below;

FIG. 6 is a side elevational View, partly in section, of the tension roller of FIG. 5;

FIG. 7 is an end view of the tension roller of FIG. 5;

FIG. 8 is an end view of a tension roller constructed as contact wheel for grinding the concave surfaces of a turbine blade;

FIG. 9 is a side elevational view, partly in section, of the tension roller of FIG. 8, and

FIG. 10 is a side elevational view, partly in section, of a spindle constructed as hollow shaft in which the spindles of the contact wheels are inserted.

DESCRIPTION OF SPECIFIC EMBODIMENT Referring to FIGS. 1 and 2, a shaft 1 is rotatably and shiftably mounted in bearing blocks 2 of a housing 3. Fixed on the right-hand end of the shaft 1 is a carrier plate 4 which carries spindles 5 and 6 of contact wheels 7 and 8 as well as tension rollers 9 associated with pairs of abrasive belts 11 and 12, The spindles 5 and 6 are driven by means of belts 13 and 14 by a driving sleeve 15 which in turn is driven by a motor 17 through the intermediary of a belt 16.

In order to immovably secure the shaft 1 in position, a bell-shaped coupling member 18 is fixed on the lefthand end of the shaft 1. A spring 19 hearing with one end against one bearing block 2 urges the shaft 1 to the right by bearing with its other end against a ring 20 secured to the shaft 1, so that the shaft 1 is prevented from continuing rotating because the bell-shaped coupling members 18 establishes, by means of friction linings 21, a firm connection with an annular coupling flange 22 of the bearing block 2.

To be able to move the abrasive belt 12 with its contact wheel 8 into the desired working position, the shaft 1 is caused to shift to a slight extent to the left by switching on an electromagnet 23 operating a disengaging lever 24, whereby the connection between the bell-shaped coupling member 18 and the coupling flange 22 of the bearing block 2 is separated. At the same time a geared motor 25 is started which rotates the bell-shaped coupling member 18 and consequently the shaft 1 by a driving means 26. This rotation continues until a switch 27 is actuated by a tripping pin 28 adjustably fixed to the bellshaped coupling member 18 and switches off the geared motor 25 and the electromagnet 23.

The tripping pin 28 is adjusted so that its switch actuating position exactly corresponds to the desired working position of the pairs of abrasive belts 11 and 12, their contact wheels 7 and 8 and, if necessary, the tension rollers 9. For each grinding position one tripping pin 28 can be used, so that the grinding position can be changed accordingly.

FIG. 3 shows how an accurate choice of the respective working height can be made by adjusting the switch 27, for which purpose the switch 27 is arranged e.g. on a swivel arm 29. The swivel arm 29 is rotatably mounted on the shaft 1 and can be adjusted by means of a handwheel 30 and a spindle 31.

As shown in FIG. 4, the abrasive belt 11 has been brought, for example, into a vertical grinding position and has an angularly adjustable grinding table 32 fixed in front thereof which, due to hingedly mounted but fixable supporting arms 33 and 34, can be moved into any desired position relative to the abrasive belt and positioned in front of any desired abrasive belt. In addition, the abrasive belt can be prevented from laterally yielding by providing a supporting table 35 for the abrasive belt.

FIGS. 5, 6 and 7 are different views of the tension roller 9, showing a carrier arm 36 for the tension roller 9 which permits, together with the tension roller, the

abrasive belt 11 or 12 to be tensioned by means of a spiral spring 37. Re-tensioning of the spring 37 to obtain any desired restoring force is possible by a taper sleeve 38 which in turn can be clamped by a nut 39 on an axle 40 of the carrier plate 4, However, in addition, the carrier arm 36 for the tension roller 9 can also be fixed in place if the tension roller 9 is to be stationary and to be used as a contact grinding wheel. The fixing of the carrier arm 36 is effected expediently with the aid of a clamping ring 42 mounted on a carrier arm sleeve 41, which clamping ring in turn can be adjusted by a threaded spindle 43 having a bearing 43a arranged on the carrier plate 4.

To ensure the parallel adjustment of the axis of the tension roller 9 to the axes of the pair of contact wheels 7 or 8, a bearing block 44 together with the tension roller 9 can be swung about an axle 45 by turning a nut 46, a restoring force being made available by a spring 47. Moreover, the tension roller 9 can be adjusted in its axial direction by slidably mounting in the bearing block 44 a bearing sleeve 48 which is externally threaded on one of its ends and can be accurately adjusted by means of a sleeve nut 49 even during the running of the tension roller 9.

To be able to carry out fine grinding operations in eyes, bores etc., the tension roller 9 can be additionally equipped with a collet 57 to permit the reception of a grinding mandrel 58.

FIGS. 8 and 9 show a specially mounted contact roller 50 which is provided instead of the tension roller 9 and which with a shaft 51 of a fork 53 is again slidably arranged in the bearing block 44. With the aid of this contact roller 50 which with a bearing axle 52 is easily exchangeably held in the fork 53, e.g. even the concave surfaces of a turbine blade 54 which are ditficult to get at can be readily ground, in which case always the optimum grinding speed corresponding to the speed of the large contact wheel 7 or 8 is available.

FIG. 10 shows a spindle 55 constructed as hollow shaft and having the spindle 6 inserted therein which is secured by means of a nut 56.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

We claim:

1. A belt grinding machine comprising (a) more than one abrasive endless belt,

(b) means mounting said endless belts in turret fashion on a carrier plate means which is rotatable to different working positions,

(c) said belt mounting means includes contact wheels and tension rollers around which each said endless belt moves,

((1) means for rotating said carrier plate means to any desired working position, and

(e) brake coupling means to stop the rotation of the carrier plate means at said desired working position and to fix the carrier plate means in place,

(f) said carrier rotating means include an axially shiftable shaft to rotate the carrier plate means, means for shifting the said shaft, and a means for engaging or disengaging the brake coupling means when said shifting means is activated.

2. A device as claimed in claim 1, wherein a spring means is provided to stress the tension rollers carrying the abrasive belts and the tension rollers are slidably adjustable in axial direction and receiving means are provided on the tension roller for the insertion of further grinding tools therein,

5 6 3. A device as claimed in claim 2, wherein the spring References Cited means comprises a spiral spring. P

4. A device as claimed in claim 2, wherein the receiving means comprises a collet. 1,011,461 12/1911 Mannmg- 5. A device as claimed in claim 2, wherein forked 1,437,414 12/1922 Gruenhagen 51' 147 receptions are provided in which the axes of the ten- 5 2,857,788 10/1958 Huhn 7764 X sion rollers are held at one end thereof and the tension rollers serve as contact wheels for grinding recessed con- ROBERT RIORDON Primary Exammer cave surfaces. JAMES F. MCKEOWN, Assistant Examiner 6. A device as claimed in claim 5, wherein driving 10 spindles for the contact wheels are constructed as hollow U.S. Cl. X.R.

shafts for the reception of grinding spindles. 51-166; 7764 

